BACKGROUNDThe accuracy of nasopharyngeal aspirate (NPA) specimens in detecting lower respiratory pathogens remains controversial. The objective of this study was to evaluate the diagnostic accuracy of aspirates (NPAs) specimen in lower respiratory tract infections (LRTIs) in children.

METHODSThe prospective study was designed to collect the data of paired NPAs and bronchoalveolar lavage fluids from children with acute LRTIs from January 2013 to December 2015. All specimens were subjected to pathogen detection: bacterial detection by culture, Mycoplasma pneumoniae (Mp) detection by polymerase chain reaction assay and virus (influenza A and B viruses, parainfluenza virus [PIV] Types 1 and 3, respiratory syncytial virus, and adenovirus) detection by immunofluorescence assay. The diagnostic accuracy analysis of NPAs was stratified by age ≤3 years (n = 194) and >3 years (n = 294).

RESULTSWe collected paired specimens from 488 children. The positive rate of pathogen was 61.6%. For Streptococcus pneumoniae, NPA culture had the specificity of 89.9% and negative predictive value of 100% in age ≤3 years, the specificity of 97.2% and negative predictive value of 98.9% in age >3 years. For Mp, the positive predictive values of NPA was 77.4% in children ≤3 years, and 89.1% in children >3 years. For PIV III, NPA specimen had the specificity of 99.8% and negative predictive value of 96.5% in children ≤3 years. For adenovirus, NPA had the specificity of 97.8% and negative predictive value of 98.4% in age ≤3 years, the specificity of 98.9% and negative predictive value of 99.3% in age >3 years.

CONCLUSIONSNPAs are less invasive diagnostic respiratory specimens, a negative NPA result is helpful in "rule out" lower airway infection; however, a positive result does not reliably "rule in" the presence of pathogens.

Acinetobacter baumannii ; isolation & purification ; pathogenicity ; Adolescent ; Child ; Child, Preschool ; Clinical Laboratory Techniques ; methods ; Enterobacter aerogenes ; isolation & purification ; pathogenicity ; Escherichia coli ; isolation & purification ; pathogenicity ; Female ; Haemophilus influenzae ; isolation & purification ; pathogenicity ; Humans ; Infant ; Male ; Nasopharynx ; microbiology ; Prospective Studies ; Pseudomonas aeruginosa ; isolation & purification ; pathogenicity ; Respiratory Tract Infections ; diagnosis ; microbiology ; Sensitivity and Specificity ; Staphylococcus aureus ; isolation & purification ; pathogenicity ; Streptococcus pneumoniae ; isolation & purification ; pathogenicity

Acinetobacter Infections ; complications ; diagnosis ; therapy ; Acinetobacter baumannii ; Animals ; Birds ; Humans ; Influenza A Virus, H7N9 Subtype ; Influenza, Human ; complications ; diagnosis ; microbiology ; therapy

BACKGROUND: Acinetobacter species are the leading cause of bloodstream infection (BSI), but their correct identification is challenging. We evaluated the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based VITEK MS (bioMerieux, France), and two automated systems, VITEK 2 (bioMerieux) and MicroScan (Siemens, USA) for identification of Acinetobacter BSI isolates. METHODS: A total of 187 BSI isolates recovered at a university hospital in Korea between 2010 and 2012 were analyzed. The identification results obtained using VITEK MS and two automated systems were compared with those of rpoB sequencing. RESULTS: Of 187 isolates analyzed, 176 were identified to the species level by rpoB sequencing: the Acinetobacter baumannii group (ABG; 101 A. baumannii, 43 A. nosocomialis, 10 A. pittii isolates) was most commonly identified (82.4%), followed by Acinetobacter genomic species 13BJ/14TU (5.3%), A. ursingii (2.1%), A. soli (2.1%), A. bereziniae (1.1%), and A. junii (1.1%). Correct identification rates to the species group (ABG) level or the species level was comparable among the three systems (VITEK MS, 90.3%; VITEK 2, 89.2%; MicroScan, 86.9%). However, VITEK MS generated fewer misidentifications (0.6%) than VITEK 2 (10.8%) and MicroScan (13.1%) (P<0.001). In addition, VITEK MS demonstrated higher specificity (100%) for discrimination between ABG and non-ABG isolates than the other systems (both, 31.8%) (P<0.001). CONCLUSIONS: The VITEK MS system is superior to the VITEK 2 and MicroScan systems for identification of Acinetobacter BSI isolates, with fewer misidentifications and better discrimination between the ABG and non-ABG isolates.
Acinetobacter/*genetics/isolation & purification ; Acinetobacter Infections/diagnosis/microbiology ; Bacterial Proteins/genetics ; Bacterial Typing Techniques/*instrumentation/*methods ; Blood/*microbiology ; DNA, Bacterial/*analysis/metabolism ; Databases, Genetic ; Humans ; *Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

No abstract available.
Acinetobacter baumannii/isolation & purification ; Adult ; Aged ; Aged, 80 and over ; Area Under Curve ; C-Reactive Protein/analysis ; Community-Acquired Infections/*diagnosis/microbiology/pathology ; Female ; Humans ; Klebsiella pneumoniae/isolation & purification ; Leukocyte Count ; Male ; Middle Aged ; Neutrophils/*cytology ; Pneumonia/*diagnosis/microbiology/pathology ; ROC Curve ; Respiratory Tract Infections/*diagnosis/microbiology/pathology ; Severity of Illness Index ; Staphylococcus aureus/isolation & purification ; Streptococcus pneumoniae/isolation & purification

BACKGROUND/AIMS: Whether the causative organism influences the clinical course of pneumonia in the intensive care unit (ICU) is controversial. We assessed the clinical manifestations and prognosis of pneumonia according to the causative pathogens in patients in a medical ICU. METHODS: A retrospective observational study was performed in a medical ICU. Among 242 patients who were admitted to the ICU, 103 who were treated for pneumonia were analyzed. RESULTS: The causative pathogen was identified in 50 patients (49.0%); 22 patients (21.6%) had multidrug-resistant (MDR) pathogens. The distribution of causative micro-organisms was Staphylococcus aureus (20%), Pseudomonas species (16%), Klebsiella pneumoniae (14%), and Acinetobacter baumannii (12%). No significant difference in ICU mortality rate, duration of ICU stay, duration of mechanical ventilation, or frequencies of re-intubation and tracheostomy were detected based on the identification of any pathogen. In sub-analyses according to the pneumonia classification, the number of pathogens identified did not differ between pneumonia types, and a higher incidence of identified MDR pathogens was detected in the hospital-acquired pneumonia group than in the community-acquired or healthcare- acquired pneumonia groups. However, the clinical outcomes of pneumonia according to identification status and type of pathogen did not differ significantly between the groups. CONCLUSIONS: Neither the causative micro-organism nor the existence of MDR pathogens in critically ill patients with pneumonia was associated with the clinical outcome of pneumonia, including ICU mortality. This result was consistent regardless of the pneumonia classification.
Acinetobacter Infections/diagnosis/*microbiology/mortality/therapy ; Aged ; Anti-Bacterial Agents/therapeutic use ; Critical Illness ; Drug Resistance, Multiple, Bacterial ; Female ; Hospital Mortality ; Humans ; Intensive Care Units ; Klebsiella Infections/diagnosis/*microbiology/mortality/therapy ; Length of Stay ; Male ; Middle Aged ; Pneumonia, Bacterial/diagnosis/*microbiology/mortality/therapy ; Proportional Hazards Models ; Pseudomonas Infections/diagnosis/*microbiology/mortality/therapy ; Respiration, Artificial ; Retrospective Studies ; Risk Factors ; Staphylococcal Infections/diagnosis/*microbiology/mortality/therapy ; Time Factors ; Tracheostomy ; Treatment Outcome

BACKGROUND: Acinetobacter baumannii is one of the most important pathogens capable of colonization in burn patients, leading to drug-resistant wound infections. This study evaluated the distribution of the AdeABC efflux system genes and their relationship to ciprofloxacin resistance in A. baumannii isolates collected from burn patients. METHODS: A total of 68 A. baumannii clinical strains were isolated from patients hospitalized in Motahari Burns Center in Tehran, Iran. Ciprofloxacin susceptibility was tested by the disk diffusion and agar dilution methods. PCR amplification of the adeRS-adeB drug efflux genes was performed for all resistant and susceptible isolates. To assess the role of the drug efflux pump in ciprofloxacin susceptibility, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was used as an efflux pump inhibitor (EPI). RESULTS: Approximately 95.6% of the Acinetobacter isolates were resistant to ciprofloxacin, with minimum inhibitory concentration (MIC) values ranging from 4 to > or =128 microg/mL. The susceptibility of 86.1% of the resistant isolates increased by factors of 2 to 64 in the presence of CCCP. All resistant isolates were positive for the adeRS-adeB genes, and 73.2% of them had mutations in the AdeRS regulatory system. CONCLUSIONS: The results showed that AdeABC genes are common in A. baumannii, which might be associated with ciprofloxacin non-susceptibility, as indicated by the observed linkage to the presence of the genes essential for the activity of the AdeABC, several single mutations occurring in the adeRS regulatory system, and an increase of ciprofloxacin susceptibility in the presence of a CCCP EPI.
ATP-Binding Cassette Transporters/antagonists & inhibitors/genetics/*metabolism ; Acinetobacter Infections/diagnosis/microbiology ; Acinetobacter baumannii/*drug effects/genetics/isolation & purification ; Anti-Bacterial Agents/*pharmacology ; Bacterial Proteins/antagonists & inhibitors/genetics/*metabolism ; Base Sequence ; Ciprofloxacin/*pharmacology ; DNA, Bacterial/chemistry/genetics/metabolism ; Drug Resistance, Bacterial ; Humans ; Hydrazones/pharmacology ; Microbial Sensitivity Tests ; Mutation ; Polymerase Chain Reaction

This study aimed to investigate whether CHROMagar Acinetobacter medium (CHROMagar, France) in combination with an antimicrobial supplement (modified CHROMagar Acinetobacter; CHROMagar, France) can be used for detecting and isolating multidrug-resistant Acinetobacter species (MRA) in nasal and rectal surveillance cultures. Nasal and rectal swab samples were collected from patients in an intensive care unit at a teaching hospital. The samples were used to inoculate modified CHROMagar Acinetobacter plates, which were examined after 24 and 48 hr of incubation at 37degrees C. Their susceptibility against the antimicrobial agents meropenem, imipenem, ciprofloxacin, and amikacin was analyzed using the Etest (bioMerieux, France). A total of 406 paired samples (406 nasal swabs and 406 rectal swabs) were obtained from 226 patients, and 120 samples (28 nasal and 28 rectal cultures, 47 nasal cultures only, and 17 rectal cultures only) yielded MRA. Seventy-five MRA isolates (18.5%) were recovered from the 406 nasal samples, and 45 MRA isolates (11.1%) were recovered from the 406 rectal samples. Of the 120 MRA isolates, 3 (2.5%) were detected only after 48 hr of incubation. The use of modified CHROMagar Acinetobacter together with nasal and rectal swabs and 1-day incubation is an effective surveillance tool for detecting MRA colonization.
Acinetobacter/drug effects/*isolation & purification ; Acinetobacter Infections/diagnosis/microbiology ; Anti-Bacterial Agents/pharmacology ; *Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Intensive Care Units ; Microbial Sensitivity Tests ; Nose/*microbiology ; Reagent Kits, Diagnostic ; Rectum/*microbiology

This study aimed to investigate whether CHROMagar Acinetobacter medium (CHROMagar, France) in combination with an antimicrobial supplement (modified CHROMagar Acinetobacter; CHROMagar, France) can be used for detecting and isolating multidrug-resistant Acinetobacter species (MRA) in nasal and rectal surveillance cultures. Nasal and rectal swab samples were collected from patients in an intensive care unit at a teaching hospital. The samples were used to inoculate modified CHROMagar Acinetobacter plates, which were examined after 24 and 48 hr of incubation at 37degrees C. Their susceptibility against the antimicrobial agents meropenem, imipenem, ciprofloxacin, and amikacin was analyzed using the Etest (bioMerieux, France). A total of 406 paired samples (406 nasal swabs and 406 rectal swabs) were obtained from 226 patients, and 120 samples (28 nasal and 28 rectal cultures, 47 nasal cultures only, and 17 rectal cultures only) yielded MRA. Seventy-five MRA isolates (18.5%) were recovered from the 406 nasal samples, and 45 MRA isolates (11.1%) were recovered from the 406 rectal samples. Of the 120 MRA isolates, 3 (2.5%) were detected only after 48 hr of incubation. The use of modified CHROMagar Acinetobacter together with nasal and rectal swabs and 1-day incubation is an effective surveillance tool for detecting MRA colonization.
Acinetobacter/drug effects/*isolation & purification ; Acinetobacter Infections/diagnosis/microbiology ; Anti-Bacterial Agents/pharmacology ; *Drug Resistance, Multiple, Bacterial/drug effects ; Humans ; Intensive Care Units ; Microbial Sensitivity Tests ; Nose/*microbiology ; Reagent Kits, Diagnostic ; Rectum/*microbiology

Acinetobacter baumannii (AB) is a common pathogen found in patients with hospital-acquired pneumonia all over the world. Community-acquired AB pneumonia, however, is very rare and has seldom been reported in Asia-Pacific countries. Community-acquired AB pneumonia has a fulminant course and is associated with a higher mortality than hospital-acquired AB pneumonia. In Korea, no case of fatal community-acquired AB pneumonia has been reported to date. Here, we describe the first fatal case of fulminant community-acquired AB pneumonia in Korea.
Acinetobacter Infections/diagnosis/*microbiology/therapy ; Acinetobacter baumannii/*isolation & purification ; Community-Acquired Infections/diagnosis/*microbiology/therapy ; Disease Progression ; Fatal Outcome ; Humans ; Male ; Middle Aged ; Republic of Korea ; Time Factors ; Treatment Failure

Acinetobacter baumannii is an important microorganism responsible for a number of nosocomial outbreaks, in particular, in intensive care units (ICUs). We investigated a nosocomial infection caused by multidrug-resistant (MDR) A. baumannii in a neonatal intensive care unit (NICU) in Korea. A. baumannii isolates were characterized using Etest (AB Biodisk, Sweden), two multiplex PCR assays, and multilocus sequence typing (MLST) scheme. PCR and PCR mapping experiments were performed for detecting and characterizing the determinants of antimicrobial resistance. Eight strains isolated from an NICU belonged to European (EU) clone II and revealed only one sequence type (ST), namely, ST357. All the isolates were susceptible to imipenem but were resistant to amikacin, gentamicin, ceftazidime, cefepime, and ciprofloxacin. To the best of our knowledge, this is the first report of a nosocomial infection in an NICU in Korea caused by ST357 MDR/carbapenem-susceptible A. baumannii strains. This result demonstrates that nosocomial outbreaks of MDR/carbapenem-susceptible strains as well as MDR/carbapenem-resistant isolates may occur in NICUs.
Acinetobacter Infections/diagnosis/*microbiology ; Acinetobacter baumannii/drug effects/genetics/*isolation & purification/metabolism ; Anti-Bacterial Agents/pharmacology ; Bacterial Proteins/genetics ; Cross Infection/*microbiology ; DNA, Bacterial/analysis ; *Drug Resistance, Multiple, Bacterial ; Humans ; Imipenem/pharmacology ; Infant, Newborn ; *Intensive Care Units, Neonatal ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Multiplex Polymerase Chain Reaction ; Republic of Korea